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authorTrond Myklebust <trond.myklebust@hammerspace.com>2019-07-16 20:51:29 +0300
committerTrond Myklebust <trond.myklebust@hammerspace.com>2019-07-18 08:12:59 +0300
commit7402a4fedc2bc448100c2d086406c708451b16dc (patch)
tree45bafb2c535f1790f99e41cb7de2b7fb0c199c4e /net/sunrpc/backchannel_rqst.c
parent9f98effc19bd490a375c4e764a56a2c015d27c3c (diff)
downloadlinux-7402a4fedc2bc448100c2d086406c708451b16dc.tar.xz
SUNRPC: Fix up backchannel slot table accounting
Add a per-transport maximum limit in the socket case, and add helpers to allow the NFSv4 code to discover that limit. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'net/sunrpc/backchannel_rqst.c')
-rw-r--r--net/sunrpc/backchannel_rqst.c40
1 files changed, 22 insertions, 18 deletions
diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c
index c47d82622fd1..339e8c077c2d 100644
--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -31,25 +31,20 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#define RPCDBG_FACILITY RPCDBG_TRANS
#endif
+#define BC_MAX_SLOTS 64U
+
+unsigned int xprt_bc_max_slots(struct rpc_xprt *xprt)
+{
+ return BC_MAX_SLOTS;
+}
+
/*
* Helper routines that track the number of preallocation elements
* on the transport.
*/
static inline int xprt_need_to_requeue(struct rpc_xprt *xprt)
{
- return xprt->bc_alloc_count < atomic_read(&xprt->bc_free_slots);
-}
-
-static inline void xprt_inc_alloc_count(struct rpc_xprt *xprt, unsigned int n)
-{
- atomic_add(n, &xprt->bc_free_slots);
- xprt->bc_alloc_count += n;
-}
-
-static inline int xprt_dec_alloc_count(struct rpc_xprt *xprt, unsigned int n)
-{
- atomic_sub(n, &xprt->bc_free_slots);
- return xprt->bc_alloc_count -= n;
+ return xprt->bc_alloc_count < xprt->bc_alloc_max;
}
/*
@@ -145,6 +140,9 @@ int xprt_setup_bc(struct rpc_xprt *xprt, unsigned int min_reqs)
dprintk("RPC: setup backchannel transport\n");
+ if (min_reqs > BC_MAX_SLOTS)
+ min_reqs = BC_MAX_SLOTS;
+
/*
* We use a temporary list to keep track of the preallocated
* buffers. Once we're done building the list we splice it
@@ -172,7 +170,9 @@ int xprt_setup_bc(struct rpc_xprt *xprt, unsigned int min_reqs)
*/
spin_lock(&xprt->bc_pa_lock);
list_splice(&tmp_list, &xprt->bc_pa_list);
- xprt_inc_alloc_count(xprt, min_reqs);
+ xprt->bc_alloc_count += min_reqs;
+ xprt->bc_alloc_max += min_reqs;
+ atomic_add(min_reqs, &xprt->bc_slot_count);
spin_unlock(&xprt->bc_pa_lock);
dprintk("RPC: setup backchannel transport done\n");
@@ -220,11 +220,13 @@ void xprt_destroy_bc(struct rpc_xprt *xprt, unsigned int max_reqs)
goto out;
spin_lock_bh(&xprt->bc_pa_lock);
- xprt_dec_alloc_count(xprt, max_reqs);
+ xprt->bc_alloc_max -= max_reqs;
list_for_each_entry_safe(req, tmp, &xprt->bc_pa_list, rq_bc_pa_list) {
dprintk("RPC: req=%p\n", req);
list_del(&req->rq_bc_pa_list);
xprt_free_allocation(req);
+ xprt->bc_alloc_count--;
+ atomic_dec(&xprt->bc_slot_count);
if (--max_reqs == 0)
break;
}
@@ -241,13 +243,14 @@ static struct rpc_rqst *xprt_get_bc_request(struct rpc_xprt *xprt, __be32 xid,
struct rpc_rqst *req = NULL;
dprintk("RPC: allocate a backchannel request\n");
- if (atomic_read(&xprt->bc_free_slots) <= 0)
- goto not_found;
if (list_empty(&xprt->bc_pa_list)) {
if (!new)
goto not_found;
+ if (atomic_read(&xprt->bc_slot_count) >= BC_MAX_SLOTS)
+ goto not_found;
list_add_tail(&new->rq_bc_pa_list, &xprt->bc_pa_list);
xprt->bc_alloc_count++;
+ atomic_inc(&xprt->bc_slot_count);
}
req = list_first_entry(&xprt->bc_pa_list, struct rpc_rqst,
rq_bc_pa_list);
@@ -291,6 +294,7 @@ void xprt_free_bc_rqst(struct rpc_rqst *req)
if (xprt_need_to_requeue(xprt)) {
list_add_tail(&req->rq_bc_pa_list, &xprt->bc_pa_list);
xprt->bc_alloc_count++;
+ atomic_inc(&xprt->bc_slot_count);
req = NULL;
}
spin_unlock_bh(&xprt->bc_pa_lock);
@@ -357,7 +361,7 @@ void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied)
spin_lock(&xprt->bc_pa_lock);
list_del(&req->rq_bc_pa_list);
- xprt_dec_alloc_count(xprt, 1);
+ xprt->bc_alloc_count--;
spin_unlock(&xprt->bc_pa_lock);
req->rq_private_buf.len = copied;